Flavor blindness and patterns of flavor symmetry breaking in lattice simulations of up, down, and strange quarks
Flavor blindness and patterns of flavor symmetry breaking in lattice simulations of up, down, and strange quarks
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DOI：
10.1103/physrevd.84.054509
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发表时间：
2011-02
影响因子：
5
通讯作者：
W. Bietenholz;V. Bornyakov;M. Göckeler;R. Horsley;W. Lockhart;Y. Nakamura;H. Perlt;D. Pleiter;P. Rakow;G. Schierholz;A. Schiller;T. Streuer;H. Stuben;F. Winter;J. Zanotti
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文献类型：
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作者：
W. Bietenholz;V. Bornyakov;M. Göckeler;R. Horsley;W. Lockhart;Y. Nakamura;H. Perlt;D. Pleiter;P. Rakow;G. Schierholz;A. Schiller;T. Streuer;H. Stuben;F. Winter;J. Zanotti
具有2+1性质(当两种夸克性质是质量简并)的QCD晶格模拟通常从相当大的上下和奇异夸克质量开始，并首先推断奇怪夸克质量，然后是向上向下夸克质量到其各自的物理值。这里我们讨论了另一种调节夸克质量的方法，在这种方法中，单态夸克质量保持不变。利用群论，首先对一般的1+1+1味情形，然后对2+1味情形，求出了关于味对称线的Taylor展开的可能的夸克质量多项式。这确保了介子的质量总是小于物理介子的质量。这种调谐夸克质量的方法使高度受约束的多项式拟合能用于将强子质量外推到它们的物理值。对于2+1味情形的数值结果证实了这种展开的有效性，对物理介子质量的外推给出了强子质量值在实验值的几个百分之一以内。单线态量保持不变，这使得晶格间距可以从强子质量确定(不一定在物理点上)。此外，还给出了该程序的扩展，以包括部分淬火的结果。
QCD lattice simulations with 2+1 flavours (when two quark flavours are mass degenerate) typically start at rather large up-down and strange quark masses and extrapolate first the strange quark mass and then the up-down quark mass to its respective physical value. Here we discuss an alternative method of tuning the quark masses, in which the singlet quark mass is kept fixed. Using group theory the possible quark mass polynomials for a Taylor expansion about the flavour symmetric line are found, first for the general 1+1+1 flavour case and then for the 2+1 flavour case. This ensures that the kaon always has mass less than the physical kaon mass. This method of tuning quark masses then enables highly constrained polynomial fits to be used in the extrapolation of hadron masses to their physical values. Numerical results for the 2+1 flavour case confirm the usefulness of this expansion and an extrapolation to the physical pion mass gives hadron mass values to within a few percent of their experimental values. Singlet quantities remain constant which allows the lattice spacing to be determined from hadron masses (without necessarily being at the physical point). Furthermore an extension of this programme to include partially quenched results is given.